include codechecks in CI

Author: tomato42

.travis.yml

@@ -43,6 +43,10 @@ matrix:
         env: TOX_ENV=py37
         dist: xenial
         sudo: true
+      - python: 3.8
+        env: TOX_ENV=codechecks
+        dist: xenial
+        sudo: true
       - python: 3.8
         env: TOX_ENV=py38
         dist: xenial